I'm currently working on a coding project and having some difficulties with this error message
ygwin/11/../../../../lib/libcygwin.a(libcmain.o): in function `main':
/usr/src/debug/cygwin-3.3.5-1/winsup/cygwin/lib/libcmain.c:37: undefined reference to `WinMain'
collect2: error: ld returned 1 exit status
I have everything properly installed this is the first time I have had this error. I know this is a segmentation fault error. I have a lot of mallocs in my code.
MAIN.C
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "image.h"
// open the file, create an ImagePPM, and return the pointer
// return NULL if the file cannot be opened
ImagePPM *readPPM(char *filename)
{
FILE *inFile = NULL;
inFile = fopen(filename,"r");
if (inFile == NULL){
return NULL;
}
ImagePPM *image = malloc(sizeof(struct _imagePPM));
fscanf(inFile, "%*s");
int numRows, numCols, limit = 0;
fscanf(inFile, "%d %d %d", &numRows , &numCols, &limit);
image -> pixels = (struct _pixel **)malloc(numRows*sizeof(struct _pixels *));
for (int i = 0 ;i < numRows; i++){
image->pixels[i] = (struct _pixel*)malloc(numCols*sizeof(struct _pixel));
}
for (int i = 0; i < numRows; i++){
for (int j = 0; j < numCols; j++){
int red, green, blue = 0;
fscanf(inFile, "%d %d %d", &red, &green, &blue);
(&(image->pixels[i][j]))->red = red;
(&(image->pixels[i][j]))->green = green;
(&(image->pixels[i][j]))->blue = blue;
}
}
strcpy(image->magic, "made it here");
image -> maxVal = limit;
image -> numRows = numRows;
image -> numCols = numCols;
fclose(inFile);
return image;
}
// open the file and write the ImagePPM to the file
// return 1 on success
// return 0 if the file cannot be opened
int writePPM(ImagePPM *pImagePPM, char *filename)
{
FILE *outFile = fopen(filename,"w");
if (outFile == NULL){
return 0;
}
fprintf(outFile, "%s\n%d\t%d\n%d\n", pImagePPM -> magic, pImagePPM ->numRows, pImagePPM -> numCols , pImagePPM -> maxVal);
for (int i = 0; i < pImagePPM -> numCols; i++){
for (int j = 0; j < pImagePPM -> numRows; j++){
Pixel *PH = &(pImagePPM -> pixels[i][j]);
fprintf(outFile, "%d %d %d ", PH -> red , PH -> green , PH -> blue);
}
fprintf(outFile, "\n");
fprintf(outFile,"made it here");
}
fclose(outFile);
return 1;
}
// free the ImagePPM and its pixels
// everything with a malloc needs a free
void freePPM(ImagePPM *pImagePPM)
{
int length = pImagePPM -> numCols;
for(int i = length -1 ; i >= 0; i--){
free(pImagePPM -> pixels[i]);
}
free(pImagePPM);
return;
}
// open the file, create an ImagePGM, and return the pointer
// return NULL if the file cannot be opened
ImagePGM *readPGM(char *filename)
{
FILE *inFile = NULL;
inFile = fopen(filename, "r");
if (inFile == NULL){
return NULL;
}
ImagePGM *image = malloc(sizeof(struct _imagePGM));
fscanf(inFile, "%*s");
int numRows, numCols , limit = 0;
fscanf(inFile, "%d %d %d", &numRows , &numCols , &limit);
image -> pixels = (int **)malloc(numRows*sizeof(int*));
for(int i = 0; i <numRows; i++){
image -> pixels[i] = (int*)malloc(numCols*sizeof(int));
}
for (int i = 0; i < numRows; i++){
for (int j = 0; j < numCols; j++){
int total = 0;
fscanf(inFile, "%d", &total);
image -> pixels[i][j] = total;
}
}
strcpy (image -> magic, "made it");
image -> maxVal = limit;
image -> numRows = numRows;
image -> numCols = numCols;
fclose(inFile);
return image;
}
// open the file and write the ImagePGM to the file
// return 1 on success
// return 0 if the file cannot be opened
int writePGM(ImagePGM *pImagePGM, char *filename)
{
FILE *outFile = NULL;
outFile = fopen(filename, "w");
if (outFile == NULL){
return 0;
}
fprintf(outFile, "%s\n%d\t%d\n%d\n",
pImagePGM->magic, pImagePGM->numRows,
pImagePGM->numCols, pImagePGM->maxVal);
for (int i = 0 ; i < pImagePGM -> numCols; i++){
for (int j = 0; j < pImagePGM -> numRows; j++){
fprintf(outFile, "%d ", pImagePGM -> pixels[i][j]);
}
fprintf(outFile, "\n");
}
fclose(outFile);
return 1;
}
// free the ImagePGM and its pixels
// everything with a malloc needs a free
void freePGM(ImagePGM *pImagePGM)
{
int numRows = pImagePGM -> numCols;
for (int i = numRows -1; i >=0; i ++){
free(pImagePGM->pixels[i]);
}
free(pImagePGM);
return ; // maybe NULL or zero
}
ImagePGM *convertToPGM(ImagePPM *pImagePPM)
{
int x ,y , max;
x = pImagePPM -> numCols;
y = pImagePPM -> numRows;
max = pImagePPM -> maxVal;
// space error
ImagePGM *image = malloc(sizeof(struct _imagePPM));
image -> pixels = (int **)malloc(x*sizeof(int*));
for (int i = 0; i < x; i++){
image -> pixels[i] = (int*)malloc(y*sizeof(int));
// error for struct needs to be fixed
}
strcpy(image -> magic, "made it here");
image -> numRows = x;
image -> numCols = y;
image -> maxVal = max;
for (int i = 0; i < x; i++){
for (int j = 0; j < y; j++){
int total = 0;
total += pImagePPM->pixels[i][j].red;
total += pImagePPM->pixels[i][j].green;
total += pImagePPM->pixels[i][j].blue;
total /=3; // converting to grey scale by / itself and 3
image -> pixels [i][j] = total;
}
}
return image;
}
ImagePGM *shrinkPGM(ImagePGM *pImagePGM)
{
int oldRow , oldCol, x, y, max;
oldRow = pImagePGM -> numRows;
oldCol = pImagePGM -> numCols;
x = oldRow/2;
y = oldCol/2;
max = pImagePGM -> maxVal;
///////////
printf("Made it here");
ImagePGM *image = malloc(sizeof(struct _imagePPM));
image -> pixels = (int **)malloc(x*sizeof(int*));
for (int i = 0; i < x; i++){
image -> pixels[i] = (int*)malloc(y*sizeof(int));
}
strcpy(image -> magic, "made it here");
image -> numRows = x;
image -> numCols = y;
image -> maxVal = max; // could be limit instead of max or max val
for(int i = 0; i < x; i++){
for(int j = 0; j < y; j++){
int total = 0;
total += pImagePGM->pixels[i*2][j*2];
total += pImagePGM->pixels[i*2][j*2+1];
total += pImagePGM->pixels[i*2+1][j*2];
total += pImagePGM->pixels[i*2+1][j*2+1];
total /= 4;
image->pixels[i][j] = total;
}
}
return image;
}
IMAGE.H
#ifndef _IMAGE_H_
#define _IMAGE_H_
typedef struct _pixel {
int red;
int green;
int blue;
} Pixel;
typedef struct _imagePPM {
char magic[3]; // magic P3
int numRows; // number of rows
int numCols; // number of columns
int maxVal; // max value of pixel colors
Pixel **pixels; // actual pixel data, a 2D array
} ImagePPM;
typedef struct _imagePGM {
char magic[3]; // magic P2
int numRows; // number of rows
int numCols; // number of columns
int maxVal; // max value of pixel colors
int **pixels; // actual pixel data, a 2D array
} ImagePGM;
ImagePPM *readPPM(char *filename);
int writePPM(ImagePPM *pImagePPM, char *filename);
void freePPM(ImagePPM *pImagePPM);
ImagePGM *readPGM(char *filename);
int writePGM(ImagePGM *pImagePGM, char *filename);
void freePGM(ImagePGM *pImagePGM);
ImagePGM *convertToPGM(ImagePPM *pImagePPM);
ImagePGM *shrinkPGM(ImagePGM *pImagePGM);
#endif
interface.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "image.h"
int main(int argc, char **argv)
{
if (argc != 4)
{
printf("Usage: %s copy-ppm input.ppm output.ppm\n", argv[0]);
printf(" %s copy-pgm input.pgm output.pgm\n", argv[0]);
printf(" %s grayscale input.ppm output.pgm\n", argv[0]);
printf(" %s shrink input.pgm output.pgm\n", argv[0]);
return 1;
}
char *command = argv[1];
char *inputFilename = argv[2];
char *outputFilename = argv[3];
if (strcmp(command, "copy-ppm") == 0)
{
ImagePPM *pImagePPM = readPPM(inputFilename);
if (pImagePPM == NULL)
{
printf("Unable to read the PPM file: %s\n", inputFilename);
return 2;
}
int success = writePPM(pImagePPM, outputFilename);
if (!success)
{
printf("Unable to write to the file: %s\n", outputFilename);
freePPM(pImagePPM);
return 3;
}
freePPM(pImagePPM);
}
else if (strcmp(command, "copy-pgm") == 0)
{
ImagePGM *pImagePGM = readPGM(inputFilename);
if (pImagePGM == NULL)
{
printf("Unable to read the PGM file: %s\n", inputFilename);
return 4;
}
int success = writePGM(pImagePGM, outputFilename);
if (!success)
{
printf("Unable to write to the file: %s\n", outputFilename);
freePGM(pImagePGM);
return 5;
}
freePGM(pImagePGM);
}
else if (strcmp(command, "grayscale") == 0)
{
ImagePPM *pImagePPM = readPPM(inputFilename);
if (pImagePPM == NULL)
{
printf("Unable to read the PPM file: %s\n", inputFilename);
return 6;
}
ImagePGM *pImagePGM = convertToPGM(pImagePPM);
int success = writePGM(pImagePGM, outputFilename);
if (!success)
{
printf("Unable to write to the file: %s\n", outputFilename);
freePPM(pImagePPM);
freePGM(pImagePGM);
return 7;
}
freePPM(pImagePPM);
freePGM(pImagePGM);
}
else if (strcmp(command, "shrink") == 0)
{
ImagePGM *pOrig = readPGM(inputFilename);
if (pOrig == NULL)
{
printf("Unable to read the PGM file: %s\n", inputFilename);
return 8;
}
ImagePGM *pShrink = shrinkPGM(pOrig);
int success = writePGM(pShrink, outputFilename);
if (!success)
{
printf("Unable to write to the file: %s\n", outputFilename);
freePGM(pOrig);
freePGM(pShrink);
return 9;
}
freePGM(pOrig);
freePGM(pShrink);
}
else
{
printf("Unrecognized command\n");
return 10;
}
return 0;
}