c99 (1)

PROLOG

NAME

SYNOPSIS

c99 [options...] pathname [[pathname] [-I directory]
    [-L directory] [-l library]]...

DESCRIPTION

$(basename pathname .c).o

OPTIONS

*

Options can be interspersed with operands.

*

The order of specifying the -L and -l options, and the order of specifying -l options with respect to pathname operands is significant.

*

Conforming applications shall specify each option separately; that is, grouping option letters (for example, -cO) need not be recognized by all implementations. The following options shall be supported:

-c

Suppress the link-edit phase of the compilation, and do not remove any object files that are produced.

-D name[=value]

Define name as if by a C-language #define directive. If no =value is given, a value of 1 shall be used. The -D option has lower precedence than the -U option. That is, if name is used in both a -U and a -D option, name shall be undefined regardless of the order of the options. Additional implementation-defined names may be provided by the compiler. Implementations shall support at least 2048 bytes of -D definitions and 256 names.

-E

Copy C-language source files to standard output, expanding all preprocessor directives; no compilation shall be performed. If any operand is not a text file, the effects are unspecified.

-g

Produce symbolic information in the object or executable files; the nature of this information is unspecified, and may be modified by implementation-defined interactions with other options.

-I directory

Change the algorithm for searching for headers whose names are not absolute pathnames to look in the directory named by the directory pathname before looking in the usual places. Thus, headers whose names are enclosed in double-quotes (dqdq) shall be searched for first in the directory of the file with the #include line, then in directories named in -I options, and last in the usual places. For headers whose names are enclosed in angle brackets (dq<>dq), the header shall be searched for only in directories named in -I options and then in the usual places. Directories named in -I options shall be searched in the order specified. If the -I option is used to specify a directory that is one of the usual places searched by default, the results are unspecified. Implementations shall support at least ten instances of this option in a single c99 command invocation.

-L directory

Change the algorithm of searching for the libraries named in the -l objects to look in the directory named by the directory pathname before looking in the usual places. Directories named in -L options shall be searched in the order specified. If the -L option is used to specify a directory that is one of the usual places searched by default, the results are unspecified. Implementations shall support at least ten instances of this option in a single c99 command invocation. If a directory specified by a -L option contains files with names starting with any of the strings dqlibc.dq, dqlibl.dq, dqlibpthread.dq, dqlibm.dq, dqlibrt.dq, dqlibtrace.dq, dqlibxnet.dq, or dqliby.dq, the results are unspecified.

-l library

Search the library named liblibrary.a. A library shall be searched when its name is encountered, so the placement of a -l option is significant. Several standard libraries can be specified in this manner, as described in the EXTENDED DESCRIPTION section. Implementations may recognize implementation-defined suffixes other than .a as denoting libraries.

-O optlevel

Specify the level of code optimization. If the optlevel option-argument is the digit '0', all special code optimizations shall be disabled. If it is the digit '1', the nature of the optimization is unspecified. If the -O option is omitted, the nature of the system's default optimization is unspecified. It is unspecified whether code generated in the presence of the -O 0 option is the same as that generated when -O is omitted. Other optlevel values may be supported.

-o outfile

Use the pathname outfile, instead of the default a.out, for the executable file produced. If the -o option is present with -c or -E, the result is unspecified.

-s

Produce object or executable files, or both, from which symbolic and other information not required for proper execution using the exec family defined in the System Interfaces volume of POSIX.1-2008 has been removed (stripped). If both -g and -s options are present, the action taken is unspecified.

-U name

Remove any initial definition of name. Multiple instances of the -D, -I, -L, -l, and -U options can be specified.

OPERANDS

file.c

A C-language source file to be compiled and optionally linked. The application shall ensure that the operand is of this form if the -c option is used.

file.a

A library of object files typically produced by the ar utility, and passed directly to the link editor. Implementations may recognize implementation-defined suffixes other than .a as denoting object file libraries.

file.o

An object file produced by c99 -c and passed directly to the link editor. Implementations may recognize implementation-defined suffixes other than .o as denoting object files. The processing of other files is implementation-defined.

STDIN

INPUT FILES

ENVIRONMENT VARIABLES

LANG

Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1-2008, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.)

LC_ALL

If set to a non-empty string value, override the values of all the other internationalization variables.

LC_CTYPE

Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments and input files).

LC_MESSAGES

Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.

NLSPATH

Determine the location of message catalogs for the processing of LC_MESSAGES.

TMPDIR

Provide a pathname that should override the default directory for temporary files, if any. On XSI-conforming systems, provide a pathname that shall override the default directory for temporary files, if any.

ASYNCHRONOUS EVENTS

STDOUT

"%s:\n", <pathname>

STDERR

"%s:\n", <pathname>

OUTPUT FILES

EXTENDED DESCRIPTION

Standard Libraries

-l c

This option shall make available all interfaces referenced in the System Interfaces volume of POSIX.1-2008, with the possible exception of those interfaces listed as residing in <aio.h>, <arpa/inet.h>, <complex.h>, <fenv.h>, <math.h>, <mqueue.h>, <netdb.h>, <net/if.h>, <netinet/in.h>, <pthread.h>, <sched.h>, <semaphore.h>, <spawn.h>, <sys/socket.h>, pthread_kill(), and pthread_sigmask() in <signal.h>, <trace.h>, interfaces marked as optional in <sys/mman.h>, interfaces marked as ADV (Advisory Information) in <fcntl.h>, and interfaces beginning with the prefix clock_ or time_ in <time.h>. This option shall not be required to be present to cause a search of this library.

-l l

This option shall make available all interfaces required by the C-language output of lex that are not made available through the -l c option.

-l pthread

This option shall make available all interfaces referenced in <pthread.h> and pthread_kill() and pthread_sigmask() referenced in <signal.h>. An implementation may search this library in the absence of this option.

-l m

This option shall make available all interfaces referenced in <math.h>, <complex.h>, and <fenv.h>. An implementation may search this library in the absence of this option.

-l rt

This option shall make available all interfaces referenced in <aio.h>, <mqueue.h>, <sched.h>, <semaphore.h>, and <spawn.h>, interfaces marked as optional in <sys/mman.h>, interfaces marked as ADV (Advisory Information) in <fcntl.h>, and interfaces beginning with the prefix clock_ and time_ in <time.h>. An implementation may search this library in the absence of this option.

-l trace

This option shall make available all interfaces referenced in <trace.h>. An implementation may search this library in the absence of this option.

-l xnet

This option shall make available all interfaces referenced in <arpa/inet.h>, <netdb.h>, <net/if.h>, <netinet/in.h>, and <sys/socket.h>. An implementation may search this library in the absence of this option.

-l y

This option shall make available all interfaces required by the C-language output of yacc that are not made available through the -l c option. In the absence of options that inhibit invocation of the link editor, such as -c or -E, the c99 utility shall cause the equivalent of a -l c option to be passed to the link editor after the last pathname operand or -l option, causing it to be searched after all other object files and libraries are loaded. It is unspecified whether the libraries libc.a, libl.a, libm.a, libpthread.a, librt.a, libtrace.a, libxnet.a, or liby.a exist as regular files. The implementation may accept as -l option-arguments names of objects that do not exist as regular files.

External Symbols

Header Search

Programming Environments

blksize_t
cc_t
mode_t
nfds_t
pid_t

_CFLAGS

To get the C compiler flags.

_LDFLAGS

To get the linker/loader flags.

_LIBS

To get the libraries. This requirement may be removed in a future version. When this utility processes a file containing a function called main(), it shall be defined with a return type equivalent to int. Using return from the initial call to main() shall be equivalent (other than with respect to language scope issues) to calling exit() with the returned value. Reaching the end of the initial call to main() shall be equivalent to calling exit(0). The implementation shall not declare a prototype for this function. Implementations provide configuration strings for C compiler flags, linker/loader flags, and libraries for each supported environment. When an application needs to use a specific programming environment rather than the implementation default programming environment while compiling, the application shall first verify that the implementation supports the desired environment. If the desired programming environment is supported, the application shall then invoke c99 with the appropriate C compiler flags as the first options for the compile, the appropriate linker/loader flags after any other options except -l but before any operands or -l options, and the appropriate libraries at the end of the operands and -l options. Conforming applications shall not attempt to link together object files compiled for different programming models. Applications shall also be aware that binary data placed in shared memory or in files might not be recognized by applications built for other programming models.

Table 4-5: Programming Environments: c99 Arguments

Programming Environment		c99 Arguments
getconf Name	Use	getconf Name
_POSIX_V7_ILP32_OFF32	C Compiler Flags	POSIX_V7_ILP32_OFF32_CFLAGS
	Linker/Loader Flags	POSIX_V7_ILP32_OFF32_LDFLAGS
	Libraries	POSIX_V7_ILP32_OFF32_LIBS
_POSIX_V7_ILP32_OFFBIG	C Compiler Flags	POSIX_V7_ILP32_OFFBIG_CFLAGS
	Linker/Loader Flags	POSIX_V7_ILP32_OFFBIG_LDFLAGS
	Libraries	POSIX_V7_ILP32_OFFBIG_LIBS
_POSIX_V7_LP64_OFF64	C Compiler Flags	POSIX_V7_LP64_OFF64_CFLAGS
	Linker/Loader Flags	POSIX_V7_LP64_OFF64_LDFLAGS
	Libraries	POSIX_V7_LP64_OFF64_LIBS
_POSIX_V7_LPBIG_OFFBIG	C Compiler Flags	POSIX_V7_LPBIG_OFFBIG_CFLAGS
	Linker/Loader Flags	POSIX_V7_LPBIG_OFFBIG_LDFLAGS
	Libraries	POSIX_V7_LPBIG_OFFBIG_LIBS

In addition to the type size programming environments above, all implementations also support a multi-threaded programming environment that is orthogonal to all of the programming environments listed above. The getconf utility can be used to get flags for the threaded programming environment, as indicated in Table 4-6, Threaded Programming Environment: c99 Arguments.

Table 4-6: Threaded Programming Environment: c99 Arguments

Programming Environment		c99 Arguments
getconf Name	Use	getconf Name
_POSIX_THREADS	C Compiler Flags	POSIX_V7_THREADS_CFLAGS
	Linker/Loader Flags	POSIX_V7_THREADS_LDFLAGS

These programming environment flags may be used in conjunction with any of the type size programming environments supported by the implementation.

EXIT STATUS

 0

Successful compilation or link edit.

>0

An error occurred.

CONSEQUENCES OF ERRORS

The following sections are informative.

APPLICATION USAGE

EXAMPLES

1.

The following usage example compiles foo.c and creates the executable file foo:

c99 -o foo foo.c

The following usage example compiles foo.c and creates the object file foo.o:

c99 -c foo.c

The following usage example compiles foo.c and creates the executable file a.out:

c99 foo.c

The following usage example compiles foo.c, links it with bar.o, and creates the executable file a.out. It may also create and leave foo.o:

c99 foo.c bar.o

2.

The following example shows how an application using threads interfaces can test for support of and use a programming environment supporting 32-bit int, long, and pointer types and an off_t type using at least 64 bits:

offbig_env=$(getconf _POSIX_V7_ILP32_OFFBIG)
if [ $offbig_env != "-1" ] && [ $offbig_env != "undefined" ]
then
    c99 $(getconf POSIX_V7_ILP32_OFFBIG_CFLAGS) \
    $(getconf POSIX_V7_THREADS_CFLAGS) -D_XOPEN_SOURCE=700 \
    $(getconf POSIX_V7_ILP32_OFFBIG_LDFLAGS) \
    $(getconf POSIX_V7_THREADS_LDFLAGS) foo.c -o foo \
    $(getconf POSIX_V7_ILP32_OFFBIG_LIBS) \
    -l pthread
else
    echo ILP32_OFFBIG programming environment not supported
    exit 1
fi

3.

The following examples clarify the use and interactions of -L and -l options.

Consider the case in which module a.c calls function f() in library libQ.a, and module b.c calls function g() in library libp.a. Assume that both libraries reside in /a/b/c. The command line to compile and link in the desired way is:

c99 -L /a/b/c main.o a.c -l Q b.c -l p

In this case the -L option need only precede the first -l option, since both libQ.a and libp.a reside in the same directory. Multiple -L options can be used when library name collisions occur. Building on the previous example, suppose that the user wants to use a new libp.a, in /a/a/a, but still wants f() from /a/b/c/libQ.a:

c99 -L /a/a/a -L /a/b/c main.o a.c -l Q b.c -l p

In this example, the linker searches the -L options in the order specified, and finds /a/a/a/libp.a before /a/b/c/libp.a when resolving references for b.c. The order of the -l options is still important, however.

4.

The following example shows how an application can use a programming environment where the widths of the following types: blksize_t, cc_t, mode_t, nfds_t, pid_t, ptrdiff_t, size_t, speed_t, ssize_t, suseconds_t, tcflag_t, wchar_t, wint_t

are no greater than the width of type long:

# First choose one of the listed environments ...
# ... if there are no additional constraints, the first one will do:
CENV=$(getconf POSIX_V7_WIDTH_RESTRICTED_ENVS | head -n l)
# ... or, if an environment that supports large files is preferred,
# look for names that contain "OFF64" or "OFFBIG". (This chooses
# the last one in the list if none match.)
for CENV in $(getconf POSIX_V7_WIDTH_RESTRICTED_ENVS)
do
    case $CENV in
    *OFF64*|*OFFBIG*) break ;;
    esac
done
# The chosen environment name can now be used like this:
c99 $(getconf ${CENV}_CFLAGS) -D _POSIX_C_SOURCE=200809L \
$(getconf ${CENV}_LDFLAGS) foo.c -o foo \
$(getconf ${CENV}_LIBS)

RATIONALE

FUTURE DIRECTIONS

SEE ALSO

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