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pass c-array via pipe
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# | |
/echo_vertices |
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import struct, sys | |
from subprocess import Popen, PIPE | |
S = struct.Struct('i f f') | |
def pack(vertices, n): | |
yield struct.pack('i', n) | |
for v in vertices: | |
yield S.pack(*v) | |
def main(): | |
try: n = int(sys.argv[1]) | |
except IndexError: | |
n = 100 | |
vertices = ((i,i+1,i+2) for i in range(n)) | |
p = Popen(["./echo_vertices", "random", "arg"], stdin=PIPE, stdout=PIPE) | |
out, _ = p.communicate(b''.join(pack(vertices, n))) | |
index, x, y = S.unpack(out) | |
assert index == (n-1) and int(x) == n and int(y) == (n+1) | |
if __name__ == '__main__': | |
main() |
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/** http://stackoverflow.com/questions/4979421/subprocess-popen-invalid-argument-broken-pipe-while-comunicating-to-c-program */ | |
#include<stdio.h> | |
#include<stdlib.h> | |
typedef struct { | |
int index; | |
float x; | |
float y; | |
} vertex; | |
int main(int argc, char* argv[]) { | |
int i; | |
vertex* VV; | |
int n = 0; | |
fread(&n, sizeof(int), 1, stdin); | |
VV =(vertex*) malloc(sizeof(vertex)*n); | |
fread(VV,sizeof(vertex),n,stdin); | |
/* write the last vertex */ | |
fwrite(&VV[n-1], sizeof(vertex), 1, stdout); | |
} |
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