system(3c) [sunos man page]

system(3C)																system(3C)

NAME

       system - issue a shell command

SYNOPSIS

       #include <stdlib.h>

       int system(const char *string);

       The  system() function causes string to be given to the shell as input, as if string had been typed as a command at a terminal. The invoker
       waits until the shell has completed, then returns the exit status of the shell in the format specified by waitpid(3C).

       If string is a null pointer, system() checks if the shell exists and is executable.  If the shell is available, system() returns a non-zero
       value; otherwise, it returns 0.	The standard to which the caller conforms determines which shell is used. See standards(5).

       The system() function executes vfork(2) to create a child process that in turn invokes one of the exec family of functions (see exec(2)) on
       the shell to execute string. If vfork() or the exec function fails, system() returns -1 and sets errno to indicate the error.

       The system() function fails if:

       EAGAIN	       The system-imposed limit on the total number of processes under execution by a single user would be exceeded.

       EINTR	       The system() function was interrupted by a signal.

       ENOMEM	       The new process requires more memory than is available.

USAGE

       The system() function manipulates the signal handlers for SIGINT, SIGQUIT, and SIGCHLD. It is therefore not safe to call system() in a mul-
       tithreaded process, since some other thread that manipulates these signal handlers and a thread that concurrently calls system() can inter-
       fere with each other in a destructive manner.  If, however, no such other thread is active, system() can safely be called concurrently from
       multiple threads. See popen(3C) for an alternative to system() that is thread-safe.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Unsafe			   |
       +-----------------------------+-----------------------------+

       ksh(1), sh(1), exec(2), vfork(2), popen(3C), waitpid(3C), attributes(5), standards(5)

								    18 Dec 2003 							system(3C)

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system(3)						     Library Functions Manual							 system(3)

NAME

       system -  Executes a shell command

LIBRARY

       Standard C Library (libc.so, libc.a)

SYNOPSIS

       #include <stdlib.h>

       int system(
	       const char *string);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       system():  XPG4, XPG4-UNIX

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Specifies a valid sh shell command.

	      If string is NULL (0), the system() function tests the accessibility of the sh command interpreter.

	      If  string  is not NULL, the system() function passes the parameter to the sh command, which interprets string as a command and exe-
	      cutes it.

DESCRIPTION

       The system() function passes the string parameter to the sh command, which interprets string as a command and executes it.

       The system() function invokes the fork() function to create a child process that in turn uses the exec function to run sh, which interprets
       the shell command contained in the string parameter.  The current process waits until the shell has completed before returning.

RETURN VALUES

       If  the	string parameter is NULL, the system() function returns 0 if it is unable to access the command interpreter or a non-zero value if
       sh is accessible.

       If the string parameter is not NULL, upon successful completion by sh, the system() function returns the exit status of the  shell  process
       in the form that wait(2) returns.  Otherwise, the system() function returns a value of -1 and sets errno to indicate the error.

       Exit status 127 indicates that the shell could not be executed.

       Note that the exit status should only be interpreted using the macros described in wait(2) and defined in the sys/wait.h header file.

ERRORS

       The  system() function sets errno to the specified values for the following conditions: The status of the child process created by system()
       is no longer available.

       In addition, the system() function may set errno values as described by fork().

RELATED INFORMATION

       Functions: exec(2), exit(2), fork(2), wait(2)

       Commands: sh(1)

       Standards: standards(5) delim off

																	 system(3)

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system(3c) [sunos man page]

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