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system(3) [netbsd man page]

SYSTEM(3)						   BSD Library Functions Manual 						 SYSTEM(3)

system -- pass a command to the shell LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <stdlib.h> int system(const char *string); DESCRIPTION
The system() function hands the argument string to the command interpreter sh(1). The calling process waits for the shell to finish execut- ing the command, ignoring SIGINT and SIGQUIT, and blocking SIGCHLD. If string is a NULL pointer, system() will return non-zero, if the command interpreter is available, or zero if none is available. Other- wise, system() returns the termination status of the shell in the format specified by waitpid(2). RETURN VALUES
If a child process cannot be created, or the termination status of the shell cannot be obtained, system() returns -1 and sets errno to indi- cate the error. If execution of the shell fails, system() returns the termination status for a program that terminates with a call of exit(127). SEE ALSO
sh(1), execve(2), waitpid(2), popen(3), shquote(3) STANDARDS
The system() function conforms to ANSI X3.159-1989 (``ANSI C89'') and IEEE Std 1003.2-1992 (``POSIX.2''). CAVEATS
Never supply the system() function with a command containing any part of an unsanitized user-supplied string. Shell meta-characters present will be honored by the sh(1) command interpreter. BSD
August 2, 2007 BSD

Check Out this Related Man Page

system(3)						     Library Functions Manual							 system(3)

system - Executes a shell command LIBRARY
Standard C Library (, 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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