NAME

xt_ff_popen() - Create a fast file stream connected to a process

LIBRARY

#include <xtend/fast-file.h>
-lxtend

SYNOPSIS

xt_ff_t *xt_ff_popen(const char *cmd, int flags)

ARGUMENTS

cmd     Full command to execute as the child, passed to sh(1)
flags   Open mode flags passed to open(3)

DESCRIPTION

xt_ff_popen(3) creates a pipe for interprocess communication, runs the specified command, connecting the command's standard input or standard output to the pipe, and returning a pointer to a xt_ff_t object connected to the other end.

It behaves much like popen(3), except that it returns a fast-file xt_ff_t pointer rather than a standard I/O FILE pointer, and accepts a full set of open(3) flags rather than the fopen(3) type strings "r", "w", etc.

This allows the calling program to spawn a child process and read its standard output or write to its standard input as easily as reading or writing a file.

Note that the stream may be closed with xt_ff_close(3). Unlike popen(3), which must be used with pclose(3), it is not necessary to call _xt_ff_pclose(3) directly. The xt_ff_close(3) function automatically determines whether the stream is attached to a pipe.

The xt_ff_t system is simpler than and much faster than traditional FILE on typical systems. It is intended for processing large files character-by-character, where low-level block I/O is not convenient, but FILE I/O causes a bottleneck.

RETURN VALUES

Pointer to a xt_ff_ile_t object on success, NULL otherwise

EXAMPLES

xt_ff_t *instream;
if ( (instream = xt_ff_popen("xzcat file.xz", O_RDONLY)) == NULL )
{


    fprintf(stderr, "Failed to read xzcat file.xz.n");


    exit(EX_NOINPUT);
}
xt_ff_close(instream);