xref: /plan9/sys/src/ape/lib/ap/stdio/fdopen.c (revision 3e12c5d1bb89fc02707907988834ef147769ddaf)
1*3e12c5d1SDavid du Colombier /*
2*3e12c5d1SDavid du Colombier  * Posix stdio -- fdopen
3*3e12c5d1SDavid du Colombier  */
4*3e12c5d1SDavid du Colombier #include "iolib.h"
5*3e12c5d1SDavid du Colombier /*
6*3e12c5d1SDavid du Colombier  * Open the named file with the given mode, using the given FILE
7*3e12c5d1SDavid du Colombier  * Legal modes are given below, `additional characters may follow these sequences':
8*3e12c5d1SDavid du Colombier  * r rb		open to read
9*3e12c5d1SDavid du Colombier  * w wb		open to write, truncating
10*3e12c5d1SDavid du Colombier  * a ab		open to write positioned at eof, creating if non-existant
11*3e12c5d1SDavid du Colombier  * r+ r+b rb+	open to read and write, creating if non-existant
12*3e12c5d1SDavid du Colombier  * w+ w+b wb+	open to read and write, truncating
13*3e12c5d1SDavid du Colombier  * a+ a+b ab+	open to read and write, positioned at eof, creating if non-existant.
14*3e12c5d1SDavid du Colombier  */
fdopen(const int fd,const char * mode)15*3e12c5d1SDavid du Colombier FILE *fdopen(const int fd, const char *mode){
16*3e12c5d1SDavid du Colombier 	FILE *f;
17*3e12c5d1SDavid du Colombier 	for(f=_IO_stream;f!=&_IO_stream[FOPEN_MAX];f++)
18*3e12c5d1SDavid du Colombier 		if(f->state==CLOSED)
19*3e12c5d1SDavid du Colombier 			break;
20*3e12c5d1SDavid du Colombier 	if(f==&_IO_stream[FOPEN_MAX])
21*3e12c5d1SDavid du Colombier 		return NULL;
22*3e12c5d1SDavid du Colombier 	f->fd=fd;
23*3e12c5d1SDavid du Colombier 	if(mode[0]=='a')
24*3e12c5d1SDavid du Colombier 		lseek(f->fd, 0L, 2);
25*3e12c5d1SDavid du Colombier 	if(f->fd==-1) return NULL;
26*3e12c5d1SDavid du Colombier 	f->flags=0;
27*3e12c5d1SDavid du Colombier 	f->state=OPEN;
28*3e12c5d1SDavid du Colombier 	f->buf=0;
29*3e12c5d1SDavid du Colombier 	f->rp=0;
30*3e12c5d1SDavid du Colombier 	f->wp=0;
31*3e12c5d1SDavid du Colombier 	f->lp=0;
32*3e12c5d1SDavid du Colombier 	return f;
33*3e12c5d1SDavid du Colombier }
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