diff --git a/include/mdso/mdso.h b/include/mdso/mdso.h
index a2ac094..a0ecb0e 100644
--- a/include/mdso/mdso.h
+++ b/include/mdso/mdso.h
@@ -158,7 +158,7 @@ mdso_api int  mdso_set_driver_fdctx     (struct mdso_driver_ctx *, const struct 
 
 /* helper api */
 mdso_api FILE*mdso_create_archive       (const struct mdso_driver_ctx *, const char * arname);
-mdso_api FILE*mdso_create_asmsrc        (const struct mdso_driver_ctx *, const char * asmname);
+mdso_api int  mdso_create_asmsrc        (const struct mdso_driver_ctx *, const char * asmname);
 mdso_api FILE*mdso_create_object        (const struct mdso_driver_ctx *, const char * objname);
 
 /* utility api */
@@ -181,9 +181,9 @@ mdso_api int  mdso_unmap_input          (struct mdso_input *);
 mdso_api uint32_t mdso_crc32_mbstr      (const unsigned char *, size_t *);
 mdso_api uint64_t mdso_crc64_mbstr      (const unsigned char *, size_t *);
 
-mdso_api int      mdso_asmgen_dsometa   (const struct mdso_driver_ctx *, FILE *);
-mdso_api int      mdso_asmgen_symentry  (const struct mdso_driver_ctx *, const char *, FILE *);
-mdso_api int      mdso_asmgen_symfn     (const struct mdso_driver_ctx *, const char *, FILE *);
+mdso_api int      mdso_asmgen_dsometa   (const struct mdso_driver_ctx *, int);
+mdso_api int      mdso_asmgen_symentry  (const struct mdso_driver_ctx *, const char *, int);
+mdso_api int      mdso_asmgen_symfn     (const struct mdso_driver_ctx *, const char *, int);
 
 mdso_api int      mdso_objgen_dsometa   (const struct mdso_driver_ctx *, FILE *, struct mdso_object *);
 mdso_api int      mdso_objgen_symentry  (const struct mdso_driver_ctx *, const char *, FILE *, struct mdso_object *);
diff --git a/src/helper/mdso_create_output.c b/src/helper/mdso_create_output.c
index f94524b..24ed757 100644
--- a/src/helper/mdso_create_output.c
+++ b/src/helper/mdso_create_output.c
@@ -58,13 +58,13 @@ FILE * mdso_create_archive(
 	return mdso_create_output_stream(dctx,arname);
 }
 
-FILE * mdso_create_asmsrc(
+int mdso_create_asmsrc(
 	const struct mdso_driver_ctx *	dctx,
 	const char *			asmname)
 {
 	return dctx->cctx->dstdir
-		? mdso_create_output_stream(dctx,asmname)
-		: stdout;
+		? mdso_create_output(dctx,asmname)
+		: mdso_driver_fdout(dctx);
 }
 
 FILE * mdso_create_object(
diff --git a/src/logic/mdso_asmgen_dsometa.c b/src/logic/mdso_asmgen_dsometa.c
index 4643e98..7c0b5ba 100644
--- a/src/logic/mdso_asmgen_dsometa.c
+++ b/src/logic/mdso_asmgen_dsometa.c
@@ -9,6 +9,7 @@
 
 #include <mdso/mdso.h>
 #include <mdso/mdso_specs.h>
+#include "mdso_dprintf_impl.h"
 #include "mdso_errinfo_impl.h"
 
 static const char * const asm_hdr_lines[] = {
@@ -40,7 +41,7 @@ static const char * const asm_libname_fmt =
 
 int mdso_asmgen_dsometa(
 	const struct mdso_driver_ctx *	dctx,
-	FILE *				fout)
+	int				fdout)
 {
 	const char * const *	line;
 	const char *		alignstr;
@@ -55,29 +56,29 @@ int mdso_asmgen_dsometa(
 	}
 
 	for (line=asm_hdr_lines; *line; line++)
-		if ((fprintf(fout,*line,dctx->cctx->libname)) < 0)
+		if ((mdso_dprintf(fdout,*line,dctx->cctx->libname)) < 0)
 			return MDSO_FILE_ERROR(dctx);
 
-	if ((fputs(alignstr,fout)) < 0)
+	if (mdso_dprintf(fdout,alignstr) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,".dsometa_%s:\n",dctx->cctx->libname)) < 0)
+	if ((mdso_dprintf(fdout,".dsometa_%s:\n",dctx->cctx->libname)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"\t%s\t%d\t\t# base\n",ptrsize,0)) < 0)
+	if ((mdso_dprintf(fdout,"\t%s\t%d\t\t# base\n",ptrsize,0)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"\t%s\t%s\t# name\n",ptrsize,".libname")) < 0)
+	if ((mdso_dprintf(fdout,"\t%s\t%s\t# name\n",ptrsize,".libname")) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"\t%s\t%u\t\t# flags\n",".long",dctx->cctx->dsoflags)) < 0)
+	if ((mdso_dprintf(fdout,"\t%s\t%u\t\t# flags\n",".long",dctx->cctx->dsoflags)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
 	for (line=asm_meta_lines; *line; line++)
-		if ((fprintf(fout,*line,ptrsize)) < 0)
+		if ((mdso_dprintf(fdout,*line,ptrsize)) < 0)
 			return MDSO_FILE_ERROR(dctx);
 
-	if (fprintf(fout,asm_libname_fmt,dctx->cctx->libname) < 0)
+	if (mdso_dprintf(fdout,asm_libname_fmt,dctx->cctx->libname) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
 	return 0;
diff --git a/src/logic/mdso_asmgen_symentry.c b/src/logic/mdso_asmgen_symentry.c
index 2b1541f..67ea686 100644
--- a/src/logic/mdso_asmgen_symentry.c
+++ b/src/logic/mdso_asmgen_symentry.c
@@ -9,6 +9,7 @@
 
 #include <mdso/mdso.h>
 #include <mdso/mdso_specs.h>
+#include "mdso_dprintf_impl.h"
 #include "mdso_errinfo_impl.h"
 
 static const char * const asm_lines[] = {
@@ -22,14 +23,14 @@ static const char * const asm_lines[] = {
 int mdso_asmgen_symentry(
 	const struct mdso_driver_ctx *	dctx,
 	const char *			sym,
-	FILE *				fout)
+	int				fdout)
 {
 	const char * const *	line;
 	const char *		alignstr;
 	const char *		ptrsize;
 	const char *		uscore;
 
-	if (fprintf(fout,"\t.file     \".%s_symentry.s\"\n",sym) < 0)
+	if (mdso_dprintf(fdout,"\t.file     \".%s_symentry.s\"\n",sym) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
 	if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
@@ -43,22 +44,22 @@ int mdso_asmgen_symentry(
 	}
 
 	for (line=asm_lines; *line; line++)
-		if ((fprintf(fout,*line,sym)) < 0)
+		if ((mdso_dprintf(fdout,*line,sym)) < 0)
 			return MDSO_FILE_ERROR(dctx);
 
-	if (fprintf(fout,"\t.globl    __imp_%s%s\n",uscore,sym) < 0)
+	if (mdso_dprintf(fdout,"\t.globl    __imp_%s%s\n",uscore,sym) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fputs(alignstr,fout)) < 0)
+	if (mdso_dprintf(fdout,alignstr) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"__imp_%s%s:\n",uscore,sym)) < 0)
+	if ((mdso_dprintf(fdout,"__imp_%s%s:\n",uscore,sym)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"\t%s\t.symstr\n",ptrsize)) < 0)
+	if ((mdso_dprintf(fdout,"\t%s\t.symstr\n",ptrsize)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
-	if ((fprintf(fout,"\t%s\t.dsometa_%s\n",ptrsize,dctx->cctx->libname)) < 0)
+	if ((mdso_dprintf(fdout,"\t%s\t.dsometa_%s\n",ptrsize,dctx->cctx->libname)) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
 	return 0;
diff --git a/src/logic/mdso_asmgen_symfn.c b/src/logic/mdso_asmgen_symfn.c
index e9484af..e63ec5d 100644
--- a/src/logic/mdso_asmgen_symfn.c
+++ b/src/logic/mdso_asmgen_symfn.c
@@ -8,6 +8,7 @@
 #include <stdio.h>
 
 #include <mdso/mdso.h>
+#include "mdso_dprintf_impl.h"
 #include "mdso_errinfo_impl.h"
 
 static const char * const asm_lines[] = {
@@ -23,19 +24,19 @@ static const char * const asm_lines[] = {
 int mdso_asmgen_symfn(
 	const struct mdso_driver_ctx *	dctx,
 	const char *			sym,
-	FILE *				fout)
+	int				fdout)
 {
 	const char * const * line;
 	const char *         uscore;
 
-	if (fprintf(fout,"\t.file     \".%s_symfn.s\"\n",sym) < 0)
+	if (mdso_dprintf(fdout,"\t.file     \".%s_symfn.s\"\n",sym) < 0)
 		return MDSO_FILE_ERROR(dctx);
 
 	uscore = (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR)
 		? "" : "_";
 
 	for (line=asm_lines; *line; line++)
-		if (fprintf(fout,*line,uscore,sym) < 0)
+		if (mdso_dprintf(fdout,*line,uscore,sym) < 0)
 			return MDSO_FILE_ERROR(dctx);
 
 	return 0;
diff --git a/src/util/mdso_create_implib_sources.c b/src/util/mdso_create_implib_sources.c
index 5c320eb..1ee647d 100644
--- a/src/util/mdso_create_implib_sources.c
+++ b/src/util/mdso_create_implib_sources.c
@@ -9,6 +9,7 @@
 #include <string.h>
 
 #include <mdso/mdso.h>
+#include "mdso_driver_impl.h"
 #include "mdso_errinfo_impl.h"
 
 static void mdso_init_asmname(char * buf, const char * fmt, const char * str)
@@ -24,11 +25,11 @@ static void mdso_init_asmname(char * buf, const char * fmt, const char * str)
 		sprintf(buf,fmt,str);
 }
 
-mdso_api int  mdso_create_implib_sources(const struct mdso_driver_ctx * dctx)
+int  mdso_create_implib_sources(const struct mdso_driver_ctx * dctx)
 {
 	struct mdso_unit_ctx *	uctx;
 	const char **		unit;
-	FILE *			fout;
+	int			fdout;
 	char			asmname[PATH_MAX];
 	const char * const *	sym;
 	int			ret;
@@ -42,13 +43,13 @@ mdso_api int  mdso_create_implib_sources(const struct mdso_driver_ctx * dctx)
 		for (sym=uctx->syms; *sym; sym++) {
 			mdso_init_asmname(asmname,".%s_symentry.s",*sym);
 
-			if (!(fout = mdso_create_asmsrc(dctx,asmname)))
+			if ((fdout = mdso_create_asmsrc(dctx,asmname)) < 0)
 				return MDSO_NESTED_ERROR(dctx);
 
-			ret = mdso_asmgen_symentry(dctx,*sym,fout);
+			ret = mdso_asmgen_symentry(dctx,*sym,fdout);
 
-			if (fout != stdout)
-				fclose(fout);
+			if (fdout != mdso_driver_fdout(dctx))
+				close(fdout);
 
 			if (ret < 0)
 				return MDSO_NESTED_ERROR(dctx);
@@ -56,13 +57,13 @@ mdso_api int  mdso_create_implib_sources(const struct mdso_driver_ctx * dctx)
 			if (uctx->stype[sym-uctx->syms] == MDSO_SYMBOL_TYPE_CODE) {
 				mdso_init_asmname(asmname,".%s_symfn.s",*sym);
 
-				if (!(fout = mdso_create_asmsrc(dctx,asmname)))
+				if ((fdout = mdso_create_asmsrc(dctx,asmname)) < 0)
 					return MDSO_NESTED_ERROR(dctx);
 
-				ret = mdso_asmgen_symfn(dctx,*sym,fout);
+				ret = mdso_asmgen_symfn(dctx,*sym,fdout);
 
-				if (fout != stdout)
-					fclose(fout);
+				if (fdout != mdso_driver_fdout(dctx))
+					close(fdout);
 
 				if (ret < 0)
 					return MDSO_NESTED_ERROR(dctx);
@@ -75,13 +76,13 @@ mdso_api int  mdso_create_implib_sources(const struct mdso_driver_ctx * dctx)
 	/* dsometa */
 	mdso_init_asmname(asmname,".dsometa_%s.s",dctx->cctx->libname);
 
-	if (!(fout = mdso_create_asmsrc(dctx,asmname)))
+	if ((fdout = mdso_create_asmsrc(dctx,asmname)) < 0)
 		return MDSO_NESTED_ERROR(dctx);
 
-	ret = mdso_asmgen_dsometa(dctx,fout);
+	ret = mdso_asmgen_dsometa(dctx,fdout);
 
-	if (fout != stdout)
-		fclose(fout);
+	if (fdout != mdso_driver_fdout(dctx))
+		close(fdout);
 
 	return (ret < 0) ? MDSO_NESTED_ERROR(dctx) : 0;
 }