Probleme read/write

#include <stdio.h>
#include <termios.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>

	char tramerecue[100];
	void envoi (int port ,char* donnee);
	void reception (int port);

int main()
{	
//	char test = atol(argv[1]);
//	printf("%s",test);

	envoi(1,"test");
	printf("envoi ok\n");
	reception(0);
	
	printf("reception envoi ok\n");
	
	if (strncmp("test",tramerecue,4)!=0) 
		{
		printf("%s",tramerecue);
		printf("erreur lors du transfert 1 vers 0\n");
		exit(1);
		}
	else printf("ok de 1 vers 0\n");
}


void envoi (int port,char *donnee)
{
	int port1;
	char buf[100];
	if (port == 0)
		{
				if ((port1=open("/dev/escc0", O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK))==-1)
				{
				perror("serial port open");
				}
				else 
				{
				fcntl(port1,F_SETFL,0);
			       }
		}
	else if (port == 1)
		{
				if ((port1=open("/dev/escc1", O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK))==-1)
				{
				perror("serial port open");
				}
				else
			 	{
				fcntl(port1,F_SETFL,0);
				}
		}
	else
		{
		printf("port non valide, le port doit etre 0 ou 1\n");
		exit(1);
		}

		strcpy(buf, donnee);
		int nbytes = strlen(buf);
		int p = write(port1, buf ,nbytes);
	//	fflush(stdout);                             ?????????????????????
		if (p<=0)
			{
			perror("write:");
			}
}

void reception (int port)
{	
	int port1;

	if (port == 0)
		{
				if ((port1=open("/dev/escc0", O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK))==-1)
				{
				perror("serial port open");
				}
				else 
				{
				fcntl(port1,F_SETFL,0);
			        }
		}
	else if (port == 1)
		{
				if ((port1=open("/dev/escc1", O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK))==-1)
				{
				perror("serial port open");
				}
				else
			 	{
				fcntl(port1,F_SETFL,0);	
       	 		}
		}
	
	else
		{
		printf("port non valide, le port doit etre 0 ou 1\n");
		exit(1);
		}
			int p=read(port1, tramerecue ,100);
			if (p<=0)
			{
			perror("erreur due à:");
			}
}