ref: 7742661aebb96a26f1cb34a68bcf631065913806
dir: /sys/src/libstdio/fdopen.c/
/*
* Posix stdio -- fdopen
*/
#include "iolib.h"
/*
* Open the named file with the given mode, using the given FILE
* Legal modes are given below, `additional characters may follow these sequences':
* r rb open to read
* w wb open to write, truncating
* a ab open to write positioned at eof, creating if non-existant
* r+ r+b rb+ open to read and write, creating if non-existant
* w+ w+b wb+ open to read and write, truncating
* a+ a+b ab+ open to read and write, positioned at eof, creating if non-existant.
*/
FILE *fdopen(const int fd, const char *mode){
FILE *f;
qlock(&_stdiolk);
for(f=_IO_stream;f!=&_IO_stream[FOPEN_MAX];f++)
if(f->state==CLOSED)
break;
if(f==&_IO_stream[FOPEN_MAX]) {
qunlock(&_stdiolk);
return NULL;
}
f->fd=fd;
if(mode[0]=='a')
seek(f->fd, 0L, 2);
if(f->fd==-1) return NULL;
f->flags=0;
f->state=OPEN;
f->buf=0;
f->rp=0;
f->wp=0;
f->lp=0;
qunlock(&_stdiolk);
return f;
}