关于我的问题，有一段代码对我有帮助，但是当我尝试对其进行编译时，关于指针存在一些错误。
我已经尝试了很多，但是指针始终是我的问题。
typedef struct
{
// The starting row.
int row;
// The starting column.
int col;
// The pointer to the board.
int (* board)[9];
} parameters;
// Prototype for the walk_rows function.
void * walk_rows(void * params);
// Prototype for the walk_cols function.
void * walk_cols(void * params);
// Prototype for 3x3 square function.
void * check_square(void * params);
/***************
* ENTRY POINT
**************/
int main(void)
{
// ====== Create the board =======
int board[9][9] = {
{6, 2, 4, 5, 3, 9, 1, 8, 7},
{5, 1, 9, 7, 2, 8, 6, 3, 4},
{8, 3, 7, 6, 1, 4, 2, 9, 5},
{1, 4, 3, 8, 6, 5, 7, 2, 9},
{9, 5, 8, 2, 4, 7, 3, 6, 1},
{7, 6, 2, 3, 9, 1, 4, 5, 8},
{3, 7, 1, 9, 5, 6, 8, 4, 2},
{4, 9, 6, 1, 8, 2, 5, 7, 3},
{2, 8, 5, 4, 7, 3, 9, 1, 6}
};
// ====== Create the parameter for the columns and rows check =======
parameters * param0 = (parameters *) malloc(sizeof(parameters));
param0->row = 0;
param0->col = 0;
param0->board = board;
// ====== Create the parameters for the 3x3 threads ======
// First 3x3
parameters * param1 = (parameters *) malloc(sizeof(parameters));
param1->row = 0;
param1->col = 0;
param1->board = board;
// Second 3x3
parameters * param2 = (parameters *) malloc(sizeof(parameters));
param2->row = 0;
param2->col = 3;
param2->board = board;
// Third 3x3
parameters * param3 = (parameters *) malloc(sizeof(parameters));
param3->row = 0;
param3->col = 6;
param3->board = board;
// Fourth 3x3
parameters * param4 = (parameters *) malloc(sizeof(parameters));
param4->row = 3;
param4->col = 0;
param4->board = board;
// Fifth 3x3
parameters * param5 = (parameters *) malloc(sizeof(parameters));
param5->row = 3;
param5->col = 3;
param5->board = board;
// Sixth 3x3
parameters * param6 = (parameters *) malloc(sizeof(parameters));
param6->row = 3;
param6->col = 6;
param6->board = board;
// Seventh 3x3
parameters * param7 = (parameters *) malloc(sizeof(parameters));
param7->row = 6;
param7->col = 0;
param7->board = board;
// Eighth 3x3
parameters * param8 = (parameters *) malloc(sizeof(parameters));
param8->row = 6;
param8->col = 3;
param8->board = board;
// Ninth 3x3
parameters * param9 = (parameters *) malloc(sizeof(parameters));
param9->row = 6;
param9->col = 6;
param9->board = board;
// ====== Create the threads ======
pthread_t thread_rows, thread_cols, thread1, thread2, thread3, thread4, thread5, thread6, thread7, thread8, thread9;
// ====== Create the return values for the threads ======
void * all_rows;
void * all_cols;
void * square1;
void * square2;
void * square3;
void * square4;
void * square5;
void * square6;
void * square7;
void * square8;
void * square9;
// ====== Initialize the threads ======
pthread_create(&thread_rows, NULL, walk_rows, (void *) param0);
pthread_create(&thread_cols, NULL, walk_cols, (void *) param0);
pthread_create(&thread1, NULL, check_square, (void *) param1);
pthread_create(&thread2, NULL, check_square, (void *) param2);
pthread_create(&thread3, NULL, check_square, (void *) param3);
pthread_create(&thread4, NULL, check_square, (void *) param4);
pthread_create(&thread5, NULL, check_square, (void *) param5);
pthread_create(&thread6, NULL, check_square, (void *) param6);
pthread_create(&thread7, NULL, check_square, (void *) param7);
pthread_create(&thread8, NULL, check_square, (void *) param8);
pthread_create(&thread9, NULL, check_square, (void *) param9);
// ======= Wait for all threads to finish their tasks =======
pthread_join(thread_rows, &all_rows);
pthread_join(thread_cols, &all_cols);
pthread_join(thread1, &square1);
pthread_join(thread2, &square2);
pthread_join(thread3, &square3);
pthread_join(thread4, &square4);
pthread_join(thread5, &square5);
pthread_join(thread6, &square6);
pthread_join(thread7, &square7);
pthread_join(thread8, &square8);
pthread_join(thread9, &square9);
// ====== Check whether the Sudoku Puzzle was solved ======
if ( (int) all_rows == 1 &&
(int) all_cols == 1 &&
(int) square1 == 1 &&
(int) square2 == 1 &&
(int) square3 == 1 &&
(int) square4 == 1 &&
(int) square5 == 1 &&
(int) square6 == 1 &&
(int) square7 == 1 &&
(int) square8 == 1 &&
(int) square9 == 1 ) {
printf("The Sudoku Puzzle is solved!\n");
}
else {
printf("The Sudoku Puzzle is NOT solved.\n");
}
return 0;
}
/**
* Checks each row if it contains all digits 1-9.
* @param void * The parameters (pointer).
* @return void * 1 if all rows contain all digits from 1-9, 0 otherwise.
*/
void * walk_rows(void * params) {
parameters * data = (parameters *) params;
int startRow = data->row;
int startCol = data->col;
for (int i = startRow; i < 9; ++i) {
int row[10] = {0};
for (int j = startCol; j < 9; ++j) {
int val = data->board[i][j];
if (row[val] != 0) {
return (void *) 0;
}
else{
row[val] = 1;
}
}
}
return (void *) 1;
}
/**
* Checks each column if it contains all digits 1-9.
* @param void * The parameters (pointer).
* @return void * 1 if all rows contain all digits from 1-9, 0 otherwise.
*/
void * walk_cols(void * params) {
parameters * data = (parameters *) params;
int startRow = data->row;
int startCol = data->col;
for (int i = startCol; i < 9; ++i) {
int col[10] = {0};
for (int j = startRow; j < 9; ++j) {
int val = data->board[j][i];
if (col[val] != 0) {
return (void *) 0;
}
else{
col[val] = 1;
}
}
}
return (void *) 1;
}
/**
* Checks if a square of size 3x3 contains all numbers from 1-9.
* @param void * The parameters (pointer).
* @return void * 1 if all rows contain all digits from 1-9, 0 otherwise.
*/
void * check_square(void * params) {
parameters * data = (parameters *) params;
int startRow = data->row;
int startCol = data->col;
int saved[10] = {0};
for (int i = startRow; i < startRow + 3; ++i) {
for (int j = startCol; j < startCol + 3; ++j) {
int val = data->board[i][j];
if (saved[val] != 0) {
return (void *) 0;
}
else{
saved[val] = 1;
}
}
}
return (void *) 1;
}
我不明白，整数和指针的大小之间是否存在差异？ 我应该为“ pthread_create”定义什么参考？
$gcc -o main *.c
main.c: In function ‘main’:
main.c:174:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
if ( (int) all_rows == 1 &&
^
main.c:175:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) all_cols == 1 &&
^
main.c:176:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square1 == 1 &&
^
main.c:177:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square2 == 1 &&
^
main.c:178:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square3 == 1 &&
^
main.c:179:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square4 == 1 &&
^
main.c:180:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square5 == 1 &&
^
main.c:181:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square6 == 1 &&
^
main.c:182:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square7 == 1 &&
^
main.c:183:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square8 == 1 &&
^
main.c:184:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
(int) square9 == 1 ) {
^
/tmp/ccz3xnwE.o: In function `main':
main.c:(.text+0x247): undefined reference to `pthread_create'
main.c:(.text+0x267): undefined reference to `pthread_create'
main.c:(.text+0x287): undefined reference to `pthread_create'
main.c:(.text+0x2a7): undefined reference to `pthread_create'
main.c:(.text+0x2c7): undefined reference to `pthread_create'
/tmp/ccz3xnwE.o:main.c:(.text+0x2e7): more undefined references to `pthread_create' follow
/tmp/ccz3xnwE.o: In function `main':
main.c:(.text+0x3a0): undefined reference to `pthread_join'
main.c:(.text+0x3b9): undefined reference to `pthread_join'
main.c:(.text+0x3d2): undefined reference to `pthread_join'
main.c:(.text+0x3eb): undefined reference to `pthread_join'
答案 0 :(得分：0)
您将指针转换为int。 您可以改为（int *）吗？
答案 1 :(得分：0)
首先，您可能需要与-lpthread链接。如果您使用的是类似Unix的操作系统。
接下来，它们不是错误，而是警告。 pthreads规范将您强制为这些类型-线程返回指针-您将其用作值。编译器需要级联转换才能关闭：
#include <stdint.h>
...
if ((int)(intptr_t)all_rows == 1)
...
尽管您可以摆脱：
if ((intptr_t)all_rows == 1)
这主要是由于广泛滥用演员表（每次您想投射某些东西时，请给自己一点点捏）。在某个时候，我预计您将需要5个层叠的强制转换才能说服编译器您知道自己在做什么：）