“错误：对具有数组类型的表达式的赋值”是什么意思？

Question

I try to compile the following code, but I constantly get this error.

    char command[100];
    FILE *fp;
    command = sprintf(command, "sudo asterisk -rx \"pjsip show aor %s\"", row[i]);
    fp = popen (command, "r");
    if (fp == NULL) {
        printf("Failed to run command\n" );
        exit(1);

This error appears: "error: assignment to expression with array type"

Answer 1

You are assigning the value of sprintf() to a variable which has array type. Arrays are not modifiable lvalues; so you can't assign to them. sprintf() returns an int -- so you need to assign its value to an int . However, I'd suggest to avoid sprintf() and use snprintf() instead. Because sprintf() is prone to buffer overflow.

int rc = snprintf(command, sizeof command, "sudo asterisk -rx \"pjsip show aor %s\"", row[i]);