CODEWITHSUNDEEP
ciodoubleprintf
user1156885
user1156885

Reputation: 51

Consecutive identical "printf" calls produce different output

I call printf function consecutively and first printf writes what it must write, second printf just writes invalid values and I guess some errors.

Type of "LOC" is defined by me and variable "i" doesn't change after callings. I checked double for any discrepancy between printf and values I give it.

i=2;
printf("x = %f,y = %f,z = %f\n",(*LOC)[0].ProjectionPoints[i].X,(*LOC)[0].ProjectionPoints[i].Y,(*LOC)[0].ProjectionPoints[i].Z); /* Prints perfectly */
printf("x = %f,y = %f,z = %f\n",(*LOC)[0].ProjectionPoints[i].X,(*LOC)[0].ProjectionPoints[i].Y,(*LOC)[0].ProjectionPoints[i].Z); /* Shows some errors and values are "0" */

First printf writes

x = -10.000000,y = -8.000000,z = -10.000000

Second printf writes

x = 0.000000,y = 0.000000,z = -1.#QNAN0

Even defining variables as const isn't change anything.

My compiler is: MS Visual C++ 2012

After I read comments;

typedef struct {
P3C_Point *ProjectionPoints;
uint Distance,LayerID,NumberOfPoints,ModelID;} P3C_LayerOnCurtain;
/* and */
P3C_LayerOnCurtain **LOC = P3C_Compile(Stream);
/* when I try printf in P3C_Compile it has no problems */

I made test before I return value, in function produces "LOC" is printf perfectly.

Answer/Solution;

 P3C_LayerOnCurtain *LOC = *P3C_Compile(Stream);

Upvotes: 1

Views: 447

Answers (1)

Medinoc
Medinoc

Reputation: 6608

The most probable cause would be that LOC or (*LOC[0].ProjectionPoints) are pointers to a local variable of a function that returned them.

If so, they would be overwritten by printf's local variables.

Upvotes: 5

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