diff --git a/include/omicron/pty.h b/include/omicron/pty.h
index ab73032..63e254d 100644
--- a/include/omicron/pty.h
+++ b/include/omicron/pty.h
@@ -1,13 +1,9 @@
 /* PTY: crea el par master/slave, lanza el hijo ya aislado y bombea E/S. */
-#ifndef OMICRON_PTY_H
-#define OMICRON_PTY_H
+#pragma  once
 
 #include <sys/types.h>
 
-#ifndef OM_POLICY_FWD
-#define OM_POLICY_FWD
 typedef struct om_policy om_policy;
-#endif
 
 /* Códigos de salida reservados del hijo: distinguen "no se ejecutó" de "falló". */
 #define OM_EXIT_SANDBOX 127 /* el sandbox no se pudo aplicar; nunca hubo exec */
@@ -26,6 +22,4 @@ int om_pty_pump(om_pty *t);
 
 int  om_pty_resize(om_pty *t, unsigned rows, unsigned cols);
 int  om_pty_wait(om_pty *t, int *status);
-void om_pty_kill(om_pty *t);
-
-#endif /* OMICRON_PTY_H */
+void om_pty_kill(om_pty *t);
\ No newline at end of file
diff --git a/src/pty.c b/src/pty.c
index 0c7b50d..a872093 100644
--- a/src/pty.c
+++ b/src/pty.c
@@ -1,45 +1,81 @@
 /* Dueño: LevtCode. Portable: usar posix_openpt, no openpty (evita #ifdef). */
-#include "omicron/pty.h"
 
+/* Macro del compilador para poder usar posix_openpt. (Debe declararse casi al principio del código) */
+#define _XOPEN_SOURCE 600
+
+#include "omicron/pty.h"
 #include "omicron/sandbox.h"
 
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
 #include <errno.h>
 
-int om_pty_spawn(char *const argv[], const om_policy *p, om_pty *t)
+int om_pty_spawn(char *const argv[], const om_policy *pol, om_pty *pty)
 {
     (void)argv;
-    (void)p;
-    (void)t;
+    (void)pol;
+    (void)pty;
     /* Orden obligatorio en el hijo: cerrar fds ANTES de om_sandbox_apply. */
     errno = ENOSYS;
     return -1;
+
+    // Hay que corregir muchas cosas, de momento, hacemos que la ejecución llegue hasta aquí
+    // y termine de forma segura.
+    char *slave_name;
+
+    pty->master_fd = posix_openpt(O_RDWR | O_NOCTTY);
+    if (pty->master_fd == -1) {
+        perror("Error in posix_openpt");
+        return EXIT_FAILURE;
+    }
+
+    if (grantpt(pty->master_fd) == -1) {
+        perror("Error in grantpt");
+        close(pty->master_fd);
+        return EXIT_FAILURE;
+    }
+
+    if (unlockpt(pty->master_fd) == -1) {
+        perror("Error in unlockpt");
+        close(pty->master_fd);
+        return EXIT_FAILURE;
+    }
+
+    slave_name = ptsname(pty->master_fd);
+    if (slave_name == NULL) {
+        perror("Error in ptsname");
+        close(pty->master_fd);
+        return EXIT_FAILURE;
+    }
 }
 
-int om_pty_pump(om_pty *t)
+int om_pty_pump(om_pty *pty)
 {
-    (void)t;
+    (void)pty;
     errno = ENOSYS;
     return -1;
 }
 
-int om_pty_resize(om_pty *t, unsigned rows, unsigned cols)
+int om_pty_resize(om_pty *pty, unsigned rows, unsigned cols)
 {
-    (void)t;
+    (void)pty;
     (void)rows;
     (void)cols;
     errno = ENOSYS;
     return -1;
 }
 
-int om_pty_wait(om_pty *t, int *status)
+int om_pty_wait(om_pty *pty, int *status)
 {
-    (void)t;
+    (void)pty;
     (void)status;
     errno = ENOSYS;
     return -1;
 }
 
-void om_pty_kill(om_pty *t)
+void om_pty_kill(om_pty *pty)
 {
-    (void)t;
+    (void)pty;
 }