管道C上的多维数组 我有一个结构，看起来像这样： struct result { int personId; int questionId; int choice; };
我正试图在父母和孩子之间建立一种双向交流。 我有一个数组： 我通过管道一行一行地发送这个2D数组，如下所示，从子部分开始：管道C上的多维数组 我有一个结构，看起来像这样： struct result { int personId; int questionId; int choice; };,c,arrays,multidimensional-array,pipe,C,Arrays,Multidimensional Array,Pipe,我正试图在父母和孩子之间建立一种双向交流。 我有一个数组： 我通过管道一行一行地发送这个2D数组，如下所示，从子部分开始： write(p2[1], &finalResults[0], sizeof(finalResults[0])); write(p2[1], &finalResults[1], sizeof(finalResults[1])); write(p2[1], &finalResults[2], sizeof(finalResults[2])); 然后我试
write(p2[1], &finalResults[0], sizeof(finalResults[0]));
write(p2[1], &finalResults[1], sizeof(finalResults[1]));
write(p2[1], &finalResults[2], sizeof(finalResults[2]));
while ((n = read(p2[0], resultBuffer, sizeof(resultBuffer)) > 0)) {
int i = 0;
for (i = 0; i < 20; ++i) {
if (resultBuffer[i].choice != 0)
printf("Result for question id: %d, person id: %d, choice: %d\n", resultBuffer[i].questionId, resultBuffer[i].personId, resultBuffer[i].choice);
}
谢谢。您没有注意到父级读取的字节数，并且可能没有足够快地关闭管道的写入端。下面是代码的一个次要变体，修复了这些问题：
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
struct result {
int personId;
int questionId;
int choice;
};
int main(void)
{
int p2[2];
pipe(p2);
if (fork() == 0)
{
close(p2[0]);
struct result finalResults[3][20];
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 20; j++)
{
finalResults[i][j].personId = rand() % 36 + 100;
finalResults[i][j].questionId = rand() % 20 + 1;
finalResults[i][j].choice = rand() % 5 + 1;
}
}
printf("Child:\n");
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 20; j++)
{
printf("(%d,%2d,%d)", finalResults[i][j].personId,
finalResults[i][j].questionId, finalResults[i][j].choice);
if (j % 5 == 4)
putchar('\n');
}
}
write(p2[1], &finalResults[0], sizeof(finalResults[0]));
write(p2[1], &finalResults[1], sizeof(finalResults[1]));
write(p2[1], &finalResults[2], sizeof(finalResults[2]));
close(p2[1]);
}
else
{
struct result resultBuffer[1024];
int n;
close(p2[1]);
while ((n = read(p2[0], resultBuffer, sizeof(resultBuffer))) > 0) {
int n_entries = n / sizeof(resultBuffer[0]);
printf("Read: %d entries\n", n_entries);
for (int i = 0; i < n_entries; ++i) {
if (resultBuffer[i].choice != 0)
printf("Result for question id: %2d, person id: %d, choice: %d\n",
resultBuffer[i].questionId, resultBuffer[i].personId,
resultBuffer[i].choice);
}
}
close(p2[0]);
}
return 0;
}
Child:
(131,10,4)(102,11,3)(124,19,4)(101, 1,1)(124, 3,3)
(111, 8,5)(116,13,4)(101,10,3)(104,14,5)(118,17,1)
(125, 7,3)(119,11,4)(119,10,5)(121, 8,3)(101,17,1)
(129, 9,2)(106,18,2)(129, 9,5)(128,11,5)(108,11,4)
(134, 7,5)(108, 2,4)(109, 9,4)(125,19,2)(107,14,1)
(122, 4,2)(105,10,1)(134,10,2)(129,16,1)(108,12,4)
(112, 4,1)(134,13,2)(116,18,4)(100, 2,3)(111, 9,3)
(126,18,3)(130, 5,5)(111, 6,1)(103,19,3)(107, 9,3)
(100,18,5)(128,16,4)(105,11,2)(106, 3,1)(122,13,3)
(109,16,3)(115, 2,1)(115,19,3)(128,11,1)(131,16,2)
(108,19,1)(103,15,4)(125, 1,1)(106, 4,2)(129,11,4)
(110, 1,5)(134,15,2)(106, 4,4)(128,11,1)(127, 4,3)
Read: 60 entries
Result for question id: 10, person id: 131, choice: 4
Result for question id: 11, person id: 102, choice: 3
Result for question id: 19, person id: 124, choice: 4
Result for question id: 1, person id: 101, choice: 1
Result for question id: 3, person id: 124, choice: 3
Result for question id: 8, person id: 111, choice: 5
Result for question id: 13, person id: 116, choice: 4
Result for question id: 10, person id: 101, choice: 3
Result for question id: 14, person id: 104, choice: 5
Result for question id: 17, person id: 118, choice: 1
Result for question id: 7, person id: 125, choice: 3
Result for question id: 11, person id: 119, choice: 4
Result for question id: 10, person id: 119, choice: 5
Result for question id: 8, person id: 121, choice: 3
Result for question id: 17, person id: 101, choice: 1
Result for question id: 9, person id: 129, choice: 2
Result for question id: 18, person id: 106, choice: 2
Result for question id: 9, person id: 129, choice: 5
Result for question id: 11, person id: 128, choice: 5
Result for question id: 11, person id: 108, choice: 4
Result for question id: 7, person id: 134, choice: 5
Result for question id: 2, person id: 108, choice: 4
Result for question id: 9, person id: 109, choice: 4
Result for question id: 19, person id: 125, choice: 2
Result for question id: 14, person id: 107, choice: 1
Result for question id: 4, person id: 122, choice: 2
Result for question id: 10, person id: 105, choice: 1
Result for question id: 10, person id: 134, choice: 2
Result for question id: 16, person id: 129, choice: 1
Result for question id: 12, person id: 108, choice: 4
Result for question id: 4, person id: 112, choice: 1
Result for question id: 13, person id: 134, choice: 2
Result for question id: 18, person id: 116, choice: 4
Result for question id: 2, person id: 100, choice: 3
Result for question id: 9, person id: 111, choice: 3
Result for question id: 18, person id: 126, choice: 3
Result for question id: 5, person id: 130, choice: 5
Result for question id: 6, person id: 111, choice: 1
Result for question id: 19, person id: 103, choice: 3
Result for question id: 9, person id: 107, choice: 3
Result for question id: 18, person id: 100, choice: 5
Result for question id: 16, person id: 128, choice: 4
Result for question id: 11, person id: 105, choice: 2
Result for question id: 3, person id: 106, choice: 1
Result for question id: 13, person id: 122, choice: 3
Result for question id: 16, person id: 109, choice: 3
Result for question id: 2, person id: 115, choice: 1
Result for question id: 19, person id: 115, choice: 3
Result for question id: 11, person id: 128, choice: 1
Result for question id: 16, person id: 131, choice: 2
Result for question id: 19, person id: 108, choice: 1
Result for question id: 15, person id: 103, choice: 4
Result for question id: 1, person id: 125, choice: 1
Result for question id: 4, person id: 106, choice: 2
Result for question id: 11, person id: 129, choice: 4
Result for question id: 1, person id: 110, choice: 5
Result for question id: 15, person id: 134, choice: 2
Result for question id: 4, person id: 106, choice: 4
Result for question id: 11, person id: 128, choice: 1
Result for question id: 4, person id: 127, choice: 3
我认为，在写入缓冲区后，在dup命令之后，您没有关闭文件描述符或文件描述符表上的缓冲区，如果您没有关闭，PROCES不理解在关闭file descriptior from TABLE之前，PROCES已完成或继续将输入写入bufer。当客户端写入第一行时，是否仅输入一次读入值的父代码，当客户端写入其他行时，不再输入此代码？@FatihAltuntaş我在写入后立即关闭它，如：closep1[0]；closep2[1]@Stephatechner没有，因为我有等待状态；在父代码中，它等待子代码完成。n的值是多少？读取可能会一次消耗所有行，但在循环中只能访问20个元素。。。
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
struct result {
int personId;
int questionId;
int choice;
};
int main(void)
{
int p2[2];
pipe(p2);
if (fork() == 0)
{
close(p2[0]);
struct result finalResults[3][20];
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 20; j++)
{
finalResults[i][j].personId = rand() % 36 + 100;
finalResults[i][j].questionId = rand() % 20 + 1;
finalResults[i][j].choice = rand() % 5 + 1;
}
}
printf("Child:\n");
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 20; j++)
{
printf("(%d,%2d,%d)", finalResults[i][j].personId,
finalResults[i][j].questionId, finalResults[i][j].choice);
if (j % 5 == 4)
putchar('\n');
}
}
write(p2[1], &finalResults[0], sizeof(finalResults[0]));
write(p2[1], &finalResults[1], sizeof(finalResults[1]));
write(p2[1], &finalResults[2], sizeof(finalResults[2]));
close(p2[1]);
}
else
{
struct result resultBuffer[1024];
int n;
close(p2[1]);
while ((n = read(p2[0], resultBuffer, sizeof(resultBuffer))) > 0) {
int n_entries = n / sizeof(resultBuffer[0]);
printf("Read: %d entries\n", n_entries);
for (int i = 0; i < n_entries; ++i) {
if (resultBuffer[i].choice != 0)
printf("Result for question id: %2d, person id: %d, choice: %d\n",
resultBuffer[i].questionId, resultBuffer[i].personId,
resultBuffer[i].choice);
}
}
close(p2[0]);
}
return 0;
}
write(p2[1], finalResults, sizeof(finalResults));
Child:
(131,10,4)(102,11,3)(124,19,4)(101, 1,1)(124, 3,3)
(111, 8,5)(116,13,4)(101,10,3)(104,14,5)(118,17,1)
(125, 7,3)(119,11,4)(119,10,5)(121, 8,3)(101,17,1)
(129, 9,2)(106,18,2)(129, 9,5)(128,11,5)(108,11,4)
(134, 7,5)(108, 2,4)(109, 9,4)(125,19,2)(107,14,1)
(122, 4,2)(105,10,1)(134,10,2)(129,16,1)(108,12,4)
(112, 4,1)(134,13,2)(116,18,4)(100, 2,3)(111, 9,3)
(126,18,3)(130, 5,5)(111, 6,1)(103,19,3)(107, 9,3)
(100,18,5)(128,16,4)(105,11,2)(106, 3,1)(122,13,3)
(109,16,3)(115, 2,1)(115,19,3)(128,11,1)(131,16,2)
(108,19,1)(103,15,4)(125, 1,1)(106, 4,2)(129,11,4)
(110, 1,5)(134,15,2)(106, 4,4)(128,11,1)(127, 4,3)
Read: 60 entries
Result for question id: 10, person id: 131, choice: 4
Result for question id: 11, person id: 102, choice: 3
Result for question id: 19, person id: 124, choice: 4
Result for question id: 1, person id: 101, choice: 1
Result for question id: 3, person id: 124, choice: 3
Result for question id: 8, person id: 111, choice: 5
Result for question id: 13, person id: 116, choice: 4
Result for question id: 10, person id: 101, choice: 3
Result for question id: 14, person id: 104, choice: 5
Result for question id: 17, person id: 118, choice: 1
Result for question id: 7, person id: 125, choice: 3
Result for question id: 11, person id: 119, choice: 4
Result for question id: 10, person id: 119, choice: 5
Result for question id: 8, person id: 121, choice: 3
Result for question id: 17, person id: 101, choice: 1
Result for question id: 9, person id: 129, choice: 2
Result for question id: 18, person id: 106, choice: 2
Result for question id: 9, person id: 129, choice: 5
Result for question id: 11, person id: 128, choice: 5
Result for question id: 11, person id: 108, choice: 4
Result for question id: 7, person id: 134, choice: 5
Result for question id: 2, person id: 108, choice: 4
Result for question id: 9, person id: 109, choice: 4
Result for question id: 19, person id: 125, choice: 2
Result for question id: 14, person id: 107, choice: 1
Result for question id: 4, person id: 122, choice: 2
Result for question id: 10, person id: 105, choice: 1
Result for question id: 10, person id: 134, choice: 2
Result for question id: 16, person id: 129, choice: 1
Result for question id: 12, person id: 108, choice: 4
Result for question id: 4, person id: 112, choice: 1
Result for question id: 13, person id: 134, choice: 2
Result for question id: 18, person id: 116, choice: 4
Result for question id: 2, person id: 100, choice: 3
Result for question id: 9, person id: 111, choice: 3
Result for question id: 18, person id: 126, choice: 3
Result for question id: 5, person id: 130, choice: 5
Result for question id: 6, person id: 111, choice: 1
Result for question id: 19, person id: 103, choice: 3
Result for question id: 9, person id: 107, choice: 3
Result for question id: 18, person id: 100, choice: 5
Result for question id: 16, person id: 128, choice: 4
Result for question id: 11, person id: 105, choice: 2
Result for question id: 3, person id: 106, choice: 1
Result for question id: 13, person id: 122, choice: 3
Result for question id: 16, person id: 109, choice: 3
Result for question id: 2, person id: 115, choice: 1
Result for question id: 19, person id: 115, choice: 3
Result for question id: 11, person id: 128, choice: 1
Result for question id: 16, person id: 131, choice: 2
Result for question id: 19, person id: 108, choice: 1
Result for question id: 15, person id: 103, choice: 4
Result for question id: 1, person id: 125, choice: 1
Result for question id: 4, person id: 106, choice: 2
Result for question id: 11, person id: 129, choice: 4
Result for question id: 1, person id: 110, choice: 5
Result for question id: 15, person id: 134, choice: 2
Result for question id: 4, person id: 106, choice: 4
Result for question id: 11, person id: 128, choice: 1
Result for question id: 4, person id: 127, choice: 3