How to add header file to Keil uVision4 project?

I get the following error when I try to build my project using Keil uVision4. Configuration\RTX_Config.c(15): error: #5: cannot open source input file "tasks.h": No such file or directory In...
How to add header file to Keil uVision4 project?

I get the following error when I try to build my project using Keil uVision4. Configuration\RTX_Config.c(15): error: #5: cannot open source input file "tasks.h": No such file or directory In...
How to add header file to project

This is my code for time delay. .#include<regx51.h> #define led P2 void delay (int i); void main() { while (1) { led = 0x01; delay(500); led = 0x01; delay(500) ; } } void delay (int i...
How to add header file to project

This is my code for time delay. .#include<regx51.h> #define led P2 void delay (int i); void main() { while (1) { led = 0x01; delay(500); led = 0x01; delay(500) ; } } void delay (int i...
HOW TO ADD sim900 HEADER TO KEIL

how can add sim900(sim900.h) header to keil. it is possible to add