我有以下代码...上的操作可能未定义?
FRAME frameArray[5][10]; // Create the array of frames
int trackBufferFull[5] = {0, 0, 0, 0, 0};// Keeps track of how full the buffer for each node is
int trackFront[5] = {0, 0, 0, 0, 0}; // Array to keep track of which is the front of the array
int trackTail[5] = {0, 0, 0, 0, 0};
// Function to add to the array (CHANGE int frame)
void addFrame (int nodeNumber, FRAME frame)
{
//Calc tail
int tail = trackTail[nodeNumber-1];
// Calc frames in buffer
int framesinBuffer = trackBufferFull[nodeNumber-1];
if (framesinBuffer == 10)
{
printf("Buffer is full\n");
}
else
{
// Add frame to frameArray
frameArray[nodeNumber-1][tail] = frame;
printf("\nAdded a frame in node: %i to the buffer\n", nodeNumber);
// Increment the count
trackBufferFull[nodeNumber-1]++;
trackTail[nodeNumber-1] = ++trackTail[nodeNumber-1] % 10;
}
}
我使用frameArray所述阵列是一个缠绕/长度10的环状阵列,因此为什么我的代码
trackTail[nodeNumber-1] = ++trackTail[nodeNumber-1] % 10;
一切完全在一个独立文件,一个较大的文件内运行然而,当我得到以下编译错误:
$ cnet GARETH -m 30
compiling gareth.c
gareth.c: In function ‘addFrame’:
gareth.c:77:27: error: operation on ‘trackTail[nodeNumber + -0x00000000000000001]’ may be undefined [-Werror=sequence-point]
gareth.c: In function ‘removeFirstFrame’:
gareth.c:98:28: error: operation on ‘trackFront[nodeNumber + -0x00000000000000001]’ may be undefined [-Werror=sequence-point]
gareth.c:105:1: error: control reaches end of non-void function [-Werror=return-type]
cc1: all warnings being treated as errors
77行是行
trackTail[nodeNumber-1] = ++trackTail[nodeNumber-1] % 10;
帮助。
要查看与行号的代码,并通过边错误的一面,我已经上传的图像: http://i.imgur.com/wyO5a.png
http://stackoverflow.com/questions/4176328/undefined-behavior-and-sequence-points - 你是_lucky_你的编译器在那里警告你。 – Mat
很少出现的问题。 +1。 – 2012-05-16 16:57:23