37 lines
734 B
C++
37 lines
734 B
C++
// RUN: %clangxx -O0 %s -o %t
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// REQUIRES: glibc
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#include <assert.h>
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#include <fcntl.h>
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#include <sys/uio.h>
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#include <unistd.h>
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#if !defined(__GLIBC_PREREQ)
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#define __GLIBC_PREREQ(a, b) 0
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#endif
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#if !__GLIBC_PREREQ(2, 26)
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#define preadv2(a, b, c, d, e) preadv(a, b, c, d)
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#endif
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int main(void) {
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int fd = open("/proc/self/stat", O_RDONLY);
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char bufa[7];
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char bufb[7];
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struct iovec vec[2];
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vec[0].iov_base = bufa + 4;
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vec[0].iov_len = 1;
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vec[1].iov_base = bufb;
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vec[1].iov_len = sizeof(bufb);
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ssize_t rd = preadv2(fd, vec, 2, 0, 0);
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assert(rd > 0);
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vec[0].iov_base = bufa;
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rd = preadv2(fd, vec, 2, 0, 0);
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assert(rd > 0);
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rd = preadv2(fd, vec, 5, -25, 0);
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assert(rd < 0);
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close(fd);
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return 0;
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}
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