49 lines
891 B
C
49 lines
891 B
C
#include <sys/types.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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// see http://www.informit.com/articles/article.aspx?p=99706&seqNum=13
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int
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main(int argc, char *argv[])
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{
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int fd, accmode, val;
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if (argc != 2)
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fd = 0;
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else
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fd = atoi(argv[1]);
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if ( (val = fcntl(fd, F_GETFL, 0)) < 0){
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perror("fcntl error for fd");
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exit(1);
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}
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printf("fcntl(%d) returns %d\n", fd, val);
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accmode = val & O_ACCMODE;
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if (accmode == O_RDONLY)
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printf("read only");
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else if (accmode == O_WRONLY)
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printf("write only");
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else if (accmode == O_RDWR)
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printf("read write");
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else {
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perror("unknown access mode");
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exit(1);
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}
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if (val & O_APPEND)
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printf(", append");
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if (val & O_NONBLOCK)
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printf(", nonblocking");
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#if !defined(_POSIX_SOURCE) && defined(O_SYNC)
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if (val & O_SYNC)
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printf(", synchronous writes");
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#endif
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putchar('\n');
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exit(0);
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}
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